/Engine/Plugins/Animation/MLDeformer/MLDeformerFramework/Source/MLDeformerFrameworkEditor/Public/MLDeformerEditorModel.h
This is called just before we start the training process. You can use it to backup any specific values that might be modified by the training process. Sometimes you want to restore specific values when the user aborts the training, while the training already modified those values.
virtual void OnPreTraining()